Bell tone apparatus for a clock

ABSTRACT

A clock, having a shaft which rotates in unison with the clock hands, is provided with a bell tone apparatus adapted to be actuated at periodic intervals to provide an audible tone. The apparatus comprises a bell mounted on the clock housing, a hammer supported by a spring adjacent the bell, and a cam mounted on the shaft for rotation with the shaft, the cam being located at a position adjacent the hammer to engage the hammer and move it progressively away from the bell as the shaft rotates. The cam is shaped to release the hammer from engagement therewith at a predetermined angular position of the rotating shaft whereby the released hammer is impelled by the spring back toward the bell to strike the bell and thereby provide an audible tone.

United States Patent Haag l l BELL TONE APPARATUS FOR A CLOCK AlbrechtHaag, Dauchingen, Germany Keinzle Uhrenfabriken Gmbl-l, Schwenningen,Germany [22} Filed: May 30, 1974 [2l] Appl. No.: 474,636

[75] Inventor:

[73] Assignee:

[ 1 Sept. 30, 1975 3.951.110 l2/l888 Aronson 58/9 PrimaryE.\'aminerLawrence R. Franklin Attorney, Agent, 0'' Firm Elliott l.Pollock 5 7 ABSTRACT A clock. having a shaft which rotates in unisonwith the clock hands, is provided with a bell tone apparatus adapted tobe actuated at periodic intervals to provide an audible tone. Theapparatus comprises a bell mounted on the clock housing, a hammersupported by a spring adjacent the bell, and a cam mounted on the shaftfor rotation with the shaft, the cam being located at a positionadjacent the hammer to engage the hammer and move it progressively awayfrom the bell as the shaft rotates. The cam is shaped to release thehammer from engagement therewith at a predetermined angular position ofthe rotating shaft whereby the released hammer is impelled by the springback toward the bell to strike the bell and thereby provide an audibletone.

9 Claims, 4 Drawing Figures U.S. Patent Sept. 30,1975 Sheet 1 of 23,908,352

U.S. Patent Sept. 30,1975 Sheet20f2 3,908,352

BELL TONE APPARATUS FOR A CLOCK BACKGROUND OF THE INVENTION The presentinvention relates to a bell tone apparatus for a clock, of the typeemploying a hammer or striker disclosed adjacent the bell and operativeto be actuated at periodic time intervals by the clockwork mechanism toprovide an audible tone which announces the elapse of each such timeinterval.

Bell tone mechanisms of the general type described are already known andcustomarily comprise a separate mechanism which employs its own drivingspring and which operates independently of the main clockwork mechanism.In these known arrangements, an actuating wheel is customarily providedwhich is released by the main clockwork mechanism at periodic timeintervals to turn, under the influence of the separate driving spring,so as to actuate the hammer and cause the hammer to strike the bell. Byappropriate design, the actuating wheel can be released every minutes,or every 30 minutes, or on the hour to cause the bell to provide anaudible tone at the selected time interval. These known arrangementsare, in general, comparatively complex and expensive, and, moreover, areusually so designed that they constitute an integral portion of the mainclockwork mechanism.

The present invention relates to a bell tone apparatus which is farsimpler in construction, and less expensive, than bell tone apparatusesofthe type described above, and which, moreover, can be readily attachedto a preexisting clockwork mechanism to provide that preexisting clockwith a bell tone sounding capability.

SUMMARY OF THE INVENTION In accordance with the present invention, aselfcontained bell tone apparatus is provided which can be readilyattached, as an additional component, to a standard clockwork mechanismto cause the clockwork mechanism to actuate the added bell toneapparatus at periodic intervals during operation of the clock thereby toprovide an audible tone at a desired time interval. The bell toneapparatus comprises a bell which is associated with a mounting structurefor attaching the bell, usually by snap connection, to a portion of theclock housing. A hammer is supported for movement adjacent the bell. Acam is attached to a rotating shaft in the clockwork mechanism, whichturns continuously in unison with the hands of the clock, e.g. the cammay be attached to the shaft which is provided for manually regulatingthe positions of the clock hands, for engaging the hammer to move itprogressively away from the bell as the main clockwork operates, and torelease the vhammer at each selected periodic time interval so as tocause the released hammer to bounce back toward the bell and strike it.

In accordance with one embodiment of the invention, the hammer is somounted that, after it has been moved away from the bell and thenreleased by the aforementioned cam,

the hammer bounces back toward its neutral or starting position underthe influence of gravitational forces. In a different embodiment of theinvention, the hammer can be supported on the 'bell mounting apparatusby a leaf spring which is back toward the bell to strike the bell whenthe hammer is released from engagement with the cam. In order to assurethat the bell is sounded at a precise time, e.g. on the hour, the camand/or the hands of the clock can be arranged for angular adjustmentrelative to one another, so that, after the bell tone mechanism of thepresent invention has been attached to the clock housing, the resultantcomposite mechanism can be readily adjusted to provide the desiredaudible tone at predetermined, precise time intervals.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing objects, advantages,construction and operation of the. present invention will become morereadily apparent from the following description and accompanyingdrawings wherein:

FIG. 1 is a side view, in partial section, of a bell tone apparatusconstructed in accordance with one embodiment of the present invention;

FIG. 2 is a plan view of the apparatus illustrated in FIG. 1;

FIG. 3 shows an adjustable clock hand arrangement which may be employedin conjunction with the bell tone apparatus of the present invention;and

FIG. 4 is a detail of a coupling plate which may be employed in thearrangement of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 and 2, thebell tone apparatus of the present invention comprises a bell 4 which issupported by a mounting structure 3 having a resilient clampingstructure 2 comprising a pair of spaced arms adapted to snap over andengage complementarily shaped support portions of the clock housing 1.Clamp 2 may be fabricated of any appropriate resilient material, e.g.metal or plastic, and, when attached to the clock housing 1, supportsthe bell 4 at a position adjacent to but spaced from said clock housing.

The mounting structure further includes a leaf spring 5 which isattached at one end to bell mount 3 and which supports, at its otherend, a hammer 6 at a position adjacent bell 4. The hammer 6 is provided,moreover, with a free end which protrudes beyond the bell 4 to aposition adjacent a cam 7 which is mounted on a shaft 8 associated withthe main clockwork mechanism, and which operates, in a manner to bedescribed hereinafter, to periodically actuate hammer 6 so as to causeit to strike bell 4.

In the form of the invention illustrated in the drawings, shaft 8constitutes a manually rotatable shaft which is provided to regulate theposition of the clock hands. To that effect, shaft 8 is connected by abeveled gear 14 to the minute hand shaft 15 of the clock. As the minutehand shaft 15 is rotated by the mainspring of the clockwork mechanism,shaft 8 will similarly be caused to rotate in unison with the clockhands. It will be appreciated, however, that some clockworks aredesigned in such a manner that a separate shaft 8, for manuallyregulating the hands of the clock, is omitted and, instead, a manualadjustment knob is attached directly to the outermost end of minute handshaft 15. When the bell tone apparatus of the present invention is to beattached to a clock of this latter type, the cam 7 is mounted directlyon the minute hand shaft 15 so as to rotate with shaft 15.

Cam 7 includes an inclined ramp surface which commences at a relativelynarrow edge 16 located below the free end of hammer 6, and which extendstherefrom in an inclined circular arc to ramp edge 17. The angulardistance between edges 16 and 17 of cam 7 is less than 360 whereby,after the free end of hammer 6 has been engaged by edge 16 of the camduring rotation of cam 7 and shaft 8, the free end of hammer 6 willremain in engagement with the inclined ramp surfa'ce of cam 7 until itreaches cam edge 17, at which time the free end of hammer 6 is released.

More particularly, as the main clockwork operates, the shaft 8, providedfor manual regulation of the hands of the clock, turns in the directionshown by the arrow in FIG. 2. During this rotation, the comparativelynarrow edge 16 of cam 7 moves under the free end of hammer 6 to causethe free end of the hammer to engage the inclined ramp surface of cam 7.As shaft 8 and cam 7 continue to rotate, the inclination of the cam rampsurface causes the free end of hammer 6 to be moved progressively awayfrom bell 4, thereby placing leaf spring 5 under progressivelyincreasing tension, and causing the spring 5 to be bent increasinglyoutwardly. When the rotation of cam 7 and shaft 8 have advanced to theposition shown in FIG. 2, the free end of hammer 6 will be released bythe cam and will drop from the end 17 of said cam, and hammer 6 is thenforcibly impelled by spring 5 back toward bell 4 to strike the bell andgenerate an audible tone. Continued rotation of shaft 8 and cam 7 beyondthis operating point will then cause the leading edge 16 of the cam toagain pass under the free end of hammer 6, to repeat the operationdescribed.

In the preferred embodiment of the invention, shaft 8 completes a singlerevolution every hour so that ham mer 6 is released to provide anaudible tone every hour on the hour. It will be apparent to thoseskilled in the art, however, that by appropriate design, e.g. byappropriate selection of gears 14 and/or the shape of cam 7, the belltone apparatus can be caused to sound every 30 minutes, or even every 15minutes.

In order to assure that the bell tone is sounded precisely at the momentwhen the minute hand of the clock points at the numeral 12 on the clockface, the cam 7 is preferably made angularly adjustable relative toshaft 8. When the bell tone apparatus has been attached to a clockhousing, the clock hands may then be regulated so that they indicate afull hour, whereafter cam 7 is rotated about its associated shaft (e.g.shaft 8) until the hammer just drops from the end 17 of the cam, and thecam is then locked to the shaft at the position so found, e.g. by a setscrew.

FIGS. 3 and 4 show an alternative adjustment arrangement which can beprovided to assure that the bell tone apparatus of the present inventionsounds at a desired precise time interval. In this particulararrangement, the hour hand shaft of the clock takes the form of a sleeve18 upon which the hour hand 19 is adjustably mounted, and the minutehand shaft 15 extends through sleeve 18 to support an adjustable minutehand 12 adjacent its forward most end 20. The end 20 of the minute handshaft 15 is threaded, and is provided with a profile which correspondsto that of the hole 11 (see FIG. 4) of a coupling plate 9 which isslipped over the end 20 of shaft 15, i.e. coupling plate 9 will rotatewith shaft 15.

The coupling plate 9 is provided with a plurality of outwardlyprotruding, sharp-edged projections 10 which engage the rear surface ofminute hand 12. Minute hand 12 in turn is provided with a circularopening through which the end 20 of shaft 15 extends. As a result,minute hand 12 can be angularly adjusted relative to shaft 15 until adesired position is reached, at whichtime minute hand 12 is locked intoplace by screwing a nut 13 onto the threaded end 20 of shaft 15 to forcethe minute hand 12 into engagement with projections 10 thereby to lockminute hand 12 to shaft 15. The hour hand 19 is pressed-fit onto hourhand shaft 18 so that it too can be moved relative to the hour handshaft 18 for purposes of adjustment if desired.

In the form of the invention shown in FIGS. 3 and 4, the rotatable shaft15 is turned until a bell tone occurs. At this position, the clock hands12 (and 19 if necessary) are adjusted relative to the correspondingshafts and relative to the clock face to indicate a full hour,whereafter the clock hands are locked into place.

Having thus described my invention, 1 claim:

1. A bell tone apparatus for attachment to a clock housing and adaptedto be actuated at periodic intervals during the operation of the clockto provide an audible tone, the clock having at least one shaft whichrotates in unison with the hands of the clock and having a portion whichis accessible from the exterior of said housing, said apparatuscomprising a bell, mounting means for attaching said bell to said clockhousing, a hammer supported by said bell mounting means for movementadjacent said bell, a cam mounted on said accessible portion of saidshaft for rotation with said shaft, said cam being located at a positionadjacent said hammer for engaging said hammer to move said hammerprogressively away from said bell as said shaft rotates, said cam beingshaped to release said hammer from engagement therewith at apredetermined angular position of said rotating shaft whereby saidreleased hammer is impelled back toward said bell to strike said belland thereby provide an audible tone when said rotating shaft reachessaid predetermined angular position.

2. The apparatus of claim 1 wherein said cam is mounted on a manuallyrotatable shaft which is provided to regulate the positions of the handsof the clock.

3. The apparatus of claim 2 wherein said manually rotatable shaft isconnected by gear means to the shaft which supports the minute hand ofthe clock.

4. The apparatus of claim 1 wherein said cam surrounds said shaft and isprovided with an inclined ramp surface which extends through an are lessthan 360.

5. The apparatus of claim 1 wherein said hammer is supported on saidbell mounting means by a spring which is placed under increasing tensionas said hammer is moved progressively away from said bell, said springbeing operative to forcibly impel said hammer toward said bell when saidhammer is released from engagement with said cam.

6. The apparatus of claim 5 wherein said bell mounting means comprisesattachment means for removably attaching said bell and its associatedspring-supported hammer to the housing of the clock.

7. The apparatus of claim 6 wherein said attachment means includesresilient means for snap connecting said apparatus to the housing of theclock.

8. The apparatus of claim 1 wherein said cam is adapted to be angularlydisplaced about said shaft, and means for locking said cam to said shaftat a desired angular position on said shaft to correlate the angular po-6 sitions of said cam and the minute hand of the clock. gular positionon the minute hand shaft of the clock to The apparatus of clam 1 whercmthe mmute hand correlate the angular positions of said cam and minute ofsaid clock is adapted to be angularly displaced relative to the minutehand shaft of the clock, and means for selectively locking said minutehand at a desired an- 5 hand.

1. A bell tone apparatus for attachment to a clock housing and adaptedto be actuated at periodic intervals during the operation of the clockto provide an audible tone, the clock having at least one shaft whichrotates in unison with the hands of the clock and having a portion whichis accessible from the exterior of said housing, said apparatuscomprising a bell, mounting means for attaching said bell to said clockhousing, a hammer supported by said bell mounting means for movementadjacent said bell, a cam mounted on said accessible portion of saidshaft for rotation with said shaft, said cam being located at a positionadjacent said hammer for engaging said hammer to move said hammerprogressively away from said bell as said shaft rotates, said cam beingshaped to release said hammer from engagement therewith at apredetermined angular position of said rotating shaft whereby saidreleased hammer is impelled back toward said bell to strike said belland thereby provide an audible tone when said rotating shaft reachessaid predetermined angular position.
 2. The apparatus of claim 1 whereinsaid cam is mounted on a manually rotatable shaft which is provided toregulate the positions of the hands of the clock.
 3. The apparatus ofclaim 2 wherein said manually rotatable shaft is connected by gear meansto the shaft which supports the minute hand of the clock.
 4. Theapparatus of claim 1 wherein said cam surrounds said shaft and isprovided with an inclined ramp surface which extends through an arc lessthan 360*.
 5. The apparatus of claim 1 wherein said hammer is supportedon said bell mounting means by a spring which is placed under increasingtension as said hammer is moved progressively away from said bell, saidspring being operative to forcibly impel said hammer toward said bellwhen said hammer is released from engagement with said cam.
 6. Theapparatus of claim 5 wherein said bell mounting means comprisesattachment means for removably attaching said bell and its associatedspring-supported hammer to the housing of the clock.
 7. The apparatus ofclaim 6 wherein said attachment means includes resilient means for snapconnecting said apparatus to the housing of the clock.
 8. The apparatusof claim 1 wherein said cam is adapted to be angularly displaced aboutsaid shaft, and means for locking said cam to said shaft at a desiredangular position on said shaft to correlate the angular positions ofsaid cam and the minute hand of the clock.
 9. The apparatus of claim 1wherein the minute hand of said clock is adapted to be angularlydisplaced relative to the minute hand shaft of the clock, and means forselectively locking said minute hand at a desired angular position onthe minute hand shaft of the clock to correlate the angular positions ofsaid cam and minute hand.